I don't have any experience with the Chicken Soup brand as it's not sold locally.

I have used the Royal Canin Holistic and I thought it was a good food. The stools did seem somewhat soft with that though.

I have Nebo on Natural Balance http://www.naturalbalanceinc.com/products/dogfood.html right now. He's been on it for quite a while now. I haven't noticed much gas and his stools are firmer than before.